Advances in technology have made automation and process control practical for many different applications. In particular, many factories and production facilities have been partially or completely automated. A number of devices, such as, for example, sensors, actuators, and controllers may be located throughout a facility, for example, to monitor and control the facility's automated process.
The sensor, actuator, and controller may be connected to a system bus. The system bus is a two-way, digital communications medium that connects the devices to a master unit. The master unit may supervise or control the devices connected to the system bus. In addition, one or more workstations may be connected to the system bus that allow operators to monitor and control the automated process using the master unit.
The master unit may include a communication interface that operates according to a specific communications protocol. All signals transmitted on the system bus are encoded according to the communications protocol specification. Each device connected to the system bus must be compatible with the communications protocol to receive commands from and to exchange data with the master unit. Therefore, only devices that have been preprogrammed to use the communications protocol may be connected with the system. As a result, for each type of device that may be used with a system, the supplier must stock devices that are compatible with each communications protocol that the supplier services. This leads to increased overhead associated with servicing more than one communications protocol. In addition, devices from a system using one communications protocol are not interchangeable with a system using another communications protocol.